Asymmetric Contribution of Blastomere Lineages of First Division of the Zygote to Entire Human Body Using Post-Zygotic Variants.

BACKGROUND: In humans, after fertilization, the zygote divides into two 2n diploid daughter blastomeres. During this division, DNA is replicated, and the remaining mutually exclusive genetic mutations in the genome of each cell are called post-zygotic variants. Using these somatic mutations, developmental lineages can be reconstructed. How these two blastomeres are contributing to the entire body is not yet identified. This study aims to evaluate the cellular contribution of two blastomeres of 2-cell embryos to the entire body in humans using post-zygotic variants based on whole genome sequencing. METHODS: Tissues from different anatomical areas were obtained from five donated cadavers for use in single-cell clonal expansion and bulk target sequencing. After conducting whole genome sequencing, computational analysis was applied to find the early embryonic mutations of each clone. We developed our in-house bioinformatics pipeline, and filtered variants using strict criteria, composed of mapping quality, base quality scores, depth, soft-clipped reads, and manual inspection, resulting in the construction of embryological phylogenetic cellular trees. RESULTS: Using our in-house pipeline for variant filtering, we could extract accurate true positive variants, and construct the embryological phylogenetic trees for each cadaver. We found that two daughter blastomeres, L1 and L2 (lineage 1 and 2, respectively), derived from the zygote, distribute unequally to the whole body at the clonal level. From bulk target sequencing data, we validated asymmetric contribution by means of the variant allele frequency of L1 and L2. The asymmetric contribution of L1 and L2 varied from person to person. CONCLUSION: We confirmed that there is asymmetric contribution of two daughter blastomeres from the first division of the zygote across the whole human body.

Yolk-Shell-Type Gold Nanoaggregates for Chemo- and Photothermal Combination Therapy for Drug-Resistant Cancers.

Epithelial ovarian cancer is a gynecological cancer with the highest mortality rate, and it exhibits resistance to conventional drugs. Gold nanospheres have gained increasing attention over the years as photothermal therapeutic nanoparticles, owing to their excellent biocompatibility, chemical stability, and ease of synthesis; however, their practical application has been hampered by their low colloidal stability and photothermal effects. In the present study, we developed a yolk-shell-structured silica nanocapsule encapsulating aggregated gold nanospheres (aAuYSs) and examined the photothermal effects of aAuYSs on cell death in drug-resistant ovarian cancers both in vitro and in vivo. The aAuYSs were synthesized using stepwise silica seed synthesis, surface amino functionalization, gold nanosphere decoration, mesoporous organosilica coating, and selective etching of the silica template. Gold nanospheres were agglomerated in the confined silica interior of aAuYSs, resulting in the red-shifting of absorbance and enhancement of the photothermal effect under 808 nm laser irradiation. The efficiency of photothermal therapy was first evaluated by inducing aAuYS-mediated cell death in A2780 ovarian cancer cells, which were cultured in a two-dimensional culture and a three-dimensional spheroid culture. We observed that photothermal therapy using aAuYSs together with doxorubicin treatment synergistically induced the cell death of doxorubicin-resistant A2780 cancer cells in vitro. Furthermore, this type of combinatorial treatment with photothermal therapy and doxorubicin synergistically inhibited the in vivo tumor growth of doxorubicin-resistant A2780 cancer cells in a xenograft transplantation model. These results suggest that photothermal therapy using aAuYSs is highly effective in the treatment of drug-resistant cancers.

Clonal dynamics in early human embryogenesis inferred from somatic mutation.

Cellular dynamics and fate decision in early human embryogenesis remain largely unknown owing to the challenges of performing studies in human embryos1. Here, we explored whole-genomes of 334 single-cell colonies and targeted deep sequences of 379 bulk tissues obtained from various anatomical locations of seven recently deceased adult human donors. Using somatic mutations as an intrinsic barcode, we reconstructed early cellular phylogenies that demonstrate (1) an endogenous mutational rate that is higher in the first cell division but decreases to approximately one per cell per cell division later in life; (2) universal unequal contribution of early cells to embryo proper, resulting from early cellular bottlenecks that stochastically set aside epiblast cells within the embryo; (3) examples of varying degrees of early clonal imbalances between tissues on the left and right sides of the body, different germ layers and specific anatomical parts and organs; (4) emergence of a few ancestral cells that will substantially contribute to adult cell pools in blood and liver; and (5) presence of mitochondrial DNA heteroplasmy in the fertilized egg. Our approach also provides insights into the age-related mutational processes and loss of sex chromosomes in normal somatic cells. In sum, this study provides a foundation for future studies to complete cellular phylogenies in human embryogenesis.

Formyl Peptide Receptor 2 Activation Ameliorates Dermal Fibrosis and Inflammation in Bleomycin-Induced Scleroderma.

Systemic sclerosis is a profibrotic autoimmune disease mediated by the dysregulation of extracellular matrix synthesis. Formyl peptide receptor 2 (Fpr2) is a G protein-coupled receptor that modulates inflammation and host defense by regulating the activation of inflammatory cells, such as macrophages. However, the role of Fpr2 in the development and therapy of scleroderma is still unclear. The present study was conducted to investigate the effects of Fpr2 activation in the treatment of scleroderma fibrosis. We found that intradermal administration of WKYMVm, an Fpr2-specific agonist, alleviated bleomycin-induced scleroderma fibrosis in mice and decreased dermal thickness in scleroderma skin. WKYMVm-treated scleroderma skin tissues displayed reduced numbers of myofibroblasts expressing α-smooth muscle actin, Vimentin, and phosphorylated SMAD3. WKYMVm treatment attenuated macrophage infiltration in scleroderma skin and reduced the number of M2 macrophages. The therapeutic effects of WKYMVm in scleroderma-associated fibrosis and inflammation were completely abrogated in Fpr2 knockout mice. Moreover, WKYMVm treatment reduced the serum levels of inflammatory cytokines, such as tumor necrosis factor-α, and interferon-γ, in the scleroderma model of wild-type mice but not in Fpr2 knockout mice. These results suggest that WKYMVm-induced activation of Fpr2 leads to alleviation of fibrosis by stimulating immune resolution in systemic sclerosis.

Role of stem cell mobilization in the treatment of ischemic diseases.

Stem cell mobilization plays important roles in the treatment of severe ischemic diseases, including myocardial infarction, limb ischemia, ischemic stroke, and acute kidney injury. Stem cell mobilization refers to the egress of heterogeneous stem cells residing in the bone marrow into the peripheral blood. In the clinic, granulocyte colony-stimulating factor (G-CSF) is the drug most commonly used to induce stem cell mobilization. Plerixafor, a direct antagonist of CXCR4, is also frequently used alone or in combination with G-CSF to mobilize stem cells. The molecular mechanisms by which G-CSF induces stem cell mobilization are well characterized. Briefly, G-CSF activates neutrophils in the bone marrow, which then release proteolytic enzymes, such as neutrophil elastase, cathepsin G, and matrix metalloproteinase 9, which cleave a variety of molecules responsible for stem cell retention in the bone marrow, including CXCL12, VCAM-1, and SCF. Subsequently, stem cells are released from the bone marrow into the peripheral blood. The released stem cells can be collected and used in autologous or allogeneic transplantation. To identify better conditions for stem cell mobilization in the treatment of acute and chronic ischemic diseases, several preclinical and clinical studies have been conducted over the past decade on various mobilizing agents. In this paper, we are going to review methods that induce mobilization of stem cells from the bone marrow and introduce the application of stem cell mobilization to therapy of ischemic diseases.

Recent advances in stem cell therapeutics and tissue engineering strategies.

BACKGROUND: Tissue regeneration includes delivering specific types of cells or cell products to injured tissues or organs for restoration of tissue and organ function. Stem cell therapy has drawn considerable attention since transplantation of stem cells can overcome the limitations of autologous transplantation of patient's tissues; however, it is not perfect for treating diseases. To overcome the hurdles associated with stem cell therapy, tissue engineering techniques have been developed. Development of stem cell technology in combination with tissue engineering has opened new ways of producing engineered tissue substitutes. Several studies have shown that this combination of tissue engineering and stem cell technologies enhances cell viability, differentiation, and therapeutic efficacy of transplanted stem cells. MAIN BODY: Stem cells that can be used for tissue regeneration include mesenchymal stem cells, embryonic stem cells, and induced pluripotent stem cells. Transplantation of stem cells alone into injured tissues exhibited low therapeutic efficacy due to poor viability and diminished regenerative activity of transplanted cells. In this review, we will discuss the progress of biomedical engineering, including scaffolds, biomaterials, and tissue engineering techniques to overcome the low therapeutic efficacy of stem cells and to treat human diseases. CONCLUSION: The combination of stem cell and tissue engineering techniques overcomes the limitations of stem cells in therapy of human diseases, and presents a new path toward regeneration of injured tissues.